FLEAS - Not just an annoying parasite


Fleas are the most common external parasite of our pets. What you see on your pet are only  the adult fleas and flea ‘dirt’; a very small proportion of the overall flea population (eggs, larvae and pupae) in your house and garden.

What Kind of Damage Can Fleas Cause?

It would be a grave mistake to think of the flea as a simple nuisance. A heavy flea burden can be lethal, especially to smaller or younger animals. Conditions brought about via flea infestation include:

• Flea Allergic Dermatitis (fleas do not make pets itchy unless the animal has a flea bite allergy)
• Flea Anaemia (slow but life-threatening blood loss)
• Feline Infectious Anaemia (a life-threatening blood parasite carried by fleas)
• Cat Scratch Fever/Bartonellosis (does not make the cat sick but the infected cat can make a person sick)
• Common Tapeworm infection (potentially harmful to children in particular)

Flea Control

The ideal flea control program utilizes products targeting the various stages of the flea life cycle, not only the adult fleas on the pet. In order to help you to select the most appropriate products to achieve a flea-free existence for everyone in your house, it is important to understand the life cycle of the flea.

The Life Cycle of the Flea: Ctenocephalides felis

Fleas have FOUR life stages. It is important to know how to break the life cycle in more than one place to achieve rapid control of the flea population both on the animal, and in your environment.

EGGS are laid in the pet’s hair coat and are designed to fall off into the environment. Eggs therefore are resistant to insecticides such as those contained in common flea treatments, but aresusceptible to particular insect growth regulator (IGR) chemicals.

LARVAE develop in the host’s environment and feed on adult flea faeces (blood) that fall out of the hair coat of the pet. Larvae are susceptible to traditional insecticides and IGR’s. Larvae eventually spin cocoons (often within carpet fibers) for their next life cycle stage, pupation.

PUPAE are resistant to freezing, heat, and insecticides. Pupae can lie dormant for many months. They are stimulated to emerge as adults by vibration, warming and increased carbon dioxide (think: hot panting dog!). Normally, this occurs when a host is near and the new flea finds the pet within seconds of emerging from its cocoon.

ADULT FLEAS are mobile and can survive a few days without a host in a suitable environment. New fleas begin feeding within hours of finding a dog or cat. Most fleas do not survive 72 hours on an animal that is itching and able to groom itself, however a female flea can begin laying eggs within 12-24 hours of that first feed. The entire life cycle of C. felis can be completed in as few as 16 days!

Options for Flea Control

Years ago, flea control meant foggers, shampoos, powders, collars, and sprays. While these products are still available, they have fallen aside in favor of a newer generation of products. It is important to understand the differences between the many products available, in order to select the most appropriate product for your situation.

For pets with a flea allergy, the most important action of the product is how quickly it kills the adult fleas. This minimises the biting/feeding opportunity for the flea which starts the allergic reaction, and if the female adult fleas can be killed within the first 12 hours it is not able to lay eggs. Therefore, over a few flea life-cycles, the flea-burden in the environment is dramatically reduced and eventually eliminated. This rapid-kill action therefore breaks the life-cycle at more than one stage and results in more rapid control of your flea problem.

Flea-only Products:

-       Comfortis® – DOGS AND CATS - a once-monthly chewable tablet, which provides a very rapid-kill of adult fleas. Studies conducted in dogs have shown that Comfortis starts to kill adult fleas within 30 minutes of oral administration and kills 100% of adult fleas within 4 hours. In cats studies conducted have shown that Comfortis starts to kill adult fleas within 30 minutes, greater than 90% die within 2 hours and 100% killed within 24 hours. It is recommended to give the tablet with food (avoid administration on empty stomach), as the  most common side-effect is vomiting post-tablet. This product also has some drug interactions and contraindications, so is important to seek veterinary advice prior to purchase or administration of the product.

-       Activyl® -  DOGS AND CATS - a once-monthly spot-on (topical) treatment. This is a new-generation flea product, with similar rapid-kill rates of adult fleas to comfortis. It has the added advantage of the active ingredient being shed from the fur and dander into the environment where it has action against the immature stages of the flea life-cycle. Activyl® starts to work quickly after it is applied, killing 90% of fleas within 2 hours of the first application. Thereafter, Activyl® kills 99% of newly arriving fleas within 8-12 hours for a full month.



Flea/Tick combined products:

-       Bravecto® - DOGS ONLY – a chewable oral treatment for both fleas and ticks, providing 3 months of sustained activity from a single-dose. This is another brand-new product, and the only one whose effect is proven to last greater than one month. Controlled trials indicate that Bravecto® kills 99% of fleas on the dog within 8 hours and 100% within 12 hours. At 12 weeks after treatment, 95.7% of new fleas are killed within 8 hours. Bravecto® is also highly effective for tick prevention. We do not have paralysis ticks here in Geelong, but if your dog travels to Gippsland or anywhere along the East coast of Australia, tick prevention is essential.

Flea/Worm combined products:

-       Sentinel® - DOGS ONLY - a once-monthly oral chewable tablet, for prevention of fleas, heartworm and intestinal worms. It is the only all-in-one complete worming product including tapeworms for dogs, so it is a useful one for families with young children. Unfortunately the flea-control is not as good as some of the previously mentioned products. The mode of action is IGR only, so adult female fleas produce eggs which do not develop into the adult stages, but it does not actually kill adult fleas. In an environment with a high flea-burden such as a household with an existing flea population, multiple pets, or cats which spend time outdoors, this product would not be sufficient on its own.

-       Panoramis® - DOGS ONLY - a once-monthly oral chewable tablet, for prevention of fleas, heartworm and intestinal worms, but excluding tapeworm. This product contains the same flea treatment as the Comfortis® mentioned above, with the addition of the intestinal worm and heartworm prevention. Similar to Comfortis®, it needs to be given with food to prevent vomiting, and does have some potential adverse interactions with other drugs. When on this product, an additional tape-worm tablet is required every 3 months.

-       Advocate® - DOGS AND CATS – a once-monthly spot-on (topical) product for prevention of fleas, heartworm and intestinal worms, but excluding tapeworm. This product contains the same flea treatment as Advantage® (flea-only). It is one of the older generation of flea treatments, and does not have the same ‘rapid-kill’ of adult fleas, allowing some to still reproduce and increase the number of fleas in the environment. When on this product, an additional tape-worm tablet is required every 3 months.

Treating the Environment:

As discussed earlier, the majority of the flea population are present in the environment, so for rapid control of fleas or when heavy infestations exist treatment of your home is important. These products are typically labelled as Cockroach Surface Sprays, with egg killers, or “last 6 months”; common brands include Raid, Baygon, Mortein. Flea bombs are also available, just ensure they are labelled as “egg killers”. Typical areas that flea eggs/larvae will hide are in carpet, underneath couches or between cushions, so thorough treatment and vacuuming afterwards is required

It is also important to wash all bedding in hot water, or even replace it when a flea infestation has occurred. Toys that can’t be washed can be placed in zip-lock bags and frozen to kill the flea eggs and larvae.

There are many more flea treatments available on the market. We have only discussed those products that we sell at Newtown Veterinary Clinic, as these are the products that we are most familiar with, and more importantly that we trust to effectively treat flea problems.

Common reasons for failure of flea control:

1)    Not treating all pets in the household with effective products regularly

2)    Not using products that are appropriate or effective  for your individual situation

3)    Regular bathing or swimming of dogs whilst using topical flea treatments – this is one of the reasons that many new products are being developed for oral administration; it is important to wait 48 HOURS before or after bathing or swimming to apply flea products topically, and even then some products are not water-fast.

Our nurses/receptionists are qualified to give you over-the-counter advice regarding flea control options. If you have a significant problem, or suspect there are medical issues associated with your flea-burdened pets, we recommend booking a consultation with one of our veterinarians for a tailored flea-control plan and management of the associated medical issues.